textproduct: Quad Cities

KEY MESSAGES

- Extreme Heat Warning continues through Thursday evening for much of the area with ongoing prolonged period of hot and very humid conditions. Daily peak heat index values of 100 to 105 and nighttime low temperatures only dropping into the mid to upper 70s.

- Humid conditions will continue into the holiday weekend. Cloud cover and slowly increasing storm chances will help to lower ambient temperatures. Storm chances will increase from the west and north into the weekend. Some storms may be strong to severe as well as have the potential to produce locally heavy rainfall.

SHORT TERM /THROUGH FRIDAY/

Issued at 213 PM CDT Wed Jul 1 2026

First, no changes to the current headlines. There is 20-33 percent probability that the heat headlines south of I-80 may need to get extended into Friday. How convection evolves over the next 24 hours will determine what will need to be done with the heat headlines across the area.

The 18z soundings has a weaker cap compared to previous days. However, there is still inhibition that needs to be overcome. Radar, however, shows weak cells developing north of Highway 30 in spite of the inhibition. Thus some isolated cells will be possible through sunset.

After sunset, the LLJ will increase with storms initiating in the LLJ and the edge of the EML. Some isolated convective cells will likely be seen north of Highway 30 during the evening. The bigger push will be after midnight when outflow boundaries from the storms in Minnesota/Wisconsin initiate additional storms in the Highway 20 corridor and possibly as far south as Highway 30.

Most storms will be below severe limits overnight but the high moisture levels in the atmosphere means locally heavy rain is a given. Precip loading in downdrafts could result in an isolated severe downburst from the stronger storms.

Some of the very short term models suggest the outflow boundary from the nocturnal convection getting as far south as I-80. Due to the overall weak forcing, the CAMs are having difficulty in developing rain that far south prior to sunrise.

By sunrise the LLJ will be in a weakening phase. Lingering convection will be mainly Highway 30 on north that will dissipate through mid-morning. Boundaries left over from the nocturnal convection will then be the foci for diurnal development Thursday afternoon.

Cloud cover from the morning convection will help suppress temperatures north of Highway 30 and should keep heat indices in the 95 to 100 range. South of Highway 30 heat indices are still expected to be over 100.

LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/

Issued at 240 AM CDT Wed Jul 1 2026

Thursday night an organized storm complex will arrive from the Plains. Damaging winds, heavy rainfall, and possibly some hail would be the main concerns.

Friday through Tuesday...Boundaries and cloud cover left over from the Thursday night storms will help to hold down temperatures and also provide boundaries for diurnal convection Friday afternoon that will continue into Friday night.

Starting Friday, rain chances will increase to 30-50% but not all areas will see rain.

Saturday through Wednesday Assessment...a certainty (>95%) that humid conditions will continue. Low (20-30%) confidence on storm timing and areal coverage.

Another disturbance moving through the Midwest Saturday and Saturday night currently looks to have the better chances to produce rain. This may or may not be in the form of an organized storm complex. Right now, the model consensus has rain chances at 30-55% with the better chances along/north of I-80.

Starting Sunday, there are additional upper level disturbances/waves progged to move through the area each day. However, there are timing differences. The main message is that while there are rain chances for each day, not everyone will see rain. Additionally, areal coverage of any precip is low at 15 to 25 percent.

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/

Issued at 1245 AM CDT Thu Jul 2 2026

Generally a VFR TAF fcst with passing high clouds and persistent south to southwesterly sfc wind of 10-15 KTs that may gust to near 20 KTs mid to late afternoon. But there is the 20-30% chance for a thunderstorm or even cluster of storms near DBQ around sunrise Thu morning(better chances off to the north). An will have to watch Thu afternoon and evening for new isolated to sctrd storm development that may get into the VCNTY of CID and DBQ. With low confidence on coverage and timing in this atmospheric set up, just went with PROB30s toward the end of the TAF period for now. If a site were to get impacted by a storm, it may be strong with gusty variable winds and sharply rain- reduced VSBYs as they pass by.

DVN WATCHES/WARNINGS/ADVISORIES

IA...Extreme Heat Warning until 10 PM CDT this evening for IAZ063>068-076>078-087>089-098-099. IL...Extreme Heat Warning until 10 PM CDT this evening for ILZ009- 015>018-024>026-034-035. MO...Extreme Heat Warning until 10 PM CDT this evening for MOZ009- 010.